The President can make a recess appointment without Senate confirmation when the Senate says it is in recess. But either the House or the Senate can take the Senate out of recess and force it to hold a "pro forma session" that will block any recess appointment. So while the President's recess appointment power is broad in theory, if either house of Congress is in the hands of the other party, it can be blocked.

The ruling invalidates hundreds of decisions made by the unconstitutionally appointed NLRB members over a more than two year period.
The Wall Street Journal notes a couple of important decisions that could be redecided:

a decision that protected workers from being fired for complaining about working conditions on sites like Facebook and a decision that gave unions greater rights in employee-discipline cases.

For a complete list of the decisions in question can be viewed over at the National Right to Work Committee website, which was compiled by former NLRB member, John Radabaugh.
Overall, the decision is a win for the preservation of the balance of power between the political branches.
However, currently, the NLRB is fully staffed with a majority of Democratic members. So there is no reason to believe that any of the purely union-biased decisions made by the unconstitutionally appointed NLRB members will be reversed.